class_docstr: Periodic Resource updater for Tune.
  
  Initially, all resources are set to 0. The updater will try to update resources
  when (1) init ResourceUpdater (2) call "update_avail_resources", "num_cpus"
  or "num_gpus".
  
  The update takes effect when (1) Ray is initialized (2) the interval between
  this and last update is larger than "refresh_period"
code: def __reduce__(self):
      # Do not need to serialize resources, because we can always
      # update it again. This also prevents keeping outdated resources
      # when deserialized.
      return _ResourceUpdater, (self._refresh_period,)
  
imports: import logging
  import os
  import time
  from collections import namedtuple
  from numbers import Number
  from typing import Any, Dict, Optional
  import ray
  from ray._private.resource_spec import NODE_ID_PREFIX
label_desc: Use image node_id 7 for calling the _ResourceUpdater obj's underlying member method code with example usage: obj.__reduce__() and returns: _ResourceUpdater,  self